afs: afs_write_end() should change i_size under the right lock

Fix afs_write_end() to change i_size under vnode->cb_lock rather than
->wb_lock so that it doesn't race with afs_vnode_commit_status() and
afs_getattr().

The ->wb_lock is only meant to guard access to ->wb_keys which isn't
accessed by that piece of code.

Fixes: 4343d00872e1 ("afs: Get rid of the afs_writeback record")
Signed-off-by: David Howells <dhowells@redhat.com>

diff --git a/fs/afs/write.c b/fs/afs/write.c
index 9270bb0..a55cb73 100644 (file)
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -194,11 +194,11 @@ int afs_write_end(struct file *file, struct address_space *mapping,
 
        i_size = i_size_read(&vnode->vfs_inode);
        if (maybe_i_size > i_size) {
-               spin_lock(&vnode->wb_lock);
+               write_seqlock(&vnode->cb_lock);
                i_size = i_size_read(&vnode->vfs_inode);
                if (maybe_i_size > i_size)
                        i_size_write(&vnode->vfs_inode, maybe_i_size);
-               spin_unlock(&vnode->wb_lock);
+               write_sequnlock(&vnode->cb_lock);
        }
 
        if (!PageUptodate(page)) {